WO2018180721A1

WO2018180721A1 - Electric motor

Info

Publication number: WO2018180721A1
Application number: PCT/JP2018/010856
Authority: WO
Inventors: 唯増田
Original assignee: Ntn株式会社
Priority date: 2017-03-28
Filing date: 2018-03-19
Publication date: 2018-10-04
Also published as: JP2018166353A

Abstract

Provided is an axial gap-type electric motor making it possible to simplify a wiring structure of a motor coil, reduce copper loss, and also reduce costs. This electric motor is an axial gap-type electric motor provided with a stator (2) and a rotor. The stator (2) has a plurality of coils (10) forming a magnetic pole and being lined up in the direction of rotation of the rotor, the coils (10) including two types, namely forward-wound coils (10a) and reverse-wound coils (10b), which have mutually different winding directions, the respective winding ends being located at each of the two ends of the axial direction. The plurality of coils (10) are composed of a plurality of coil groups (11) each constituted by forward-wound coils (10a) and reverse-wound coils (10b) lining up so as to alternate in the direction of rotation. In a plurality of coils constituting the same coil group (11), between coils that are adjacent in the circumferential direction, winding ends thereof having mutually the same axial direction are bonded.

Description

Electric motor

Related applications

This application claims the priority of Japanese Patent Application No. 2017-062139 filed on Mar. 28, 2017, which is incorporated herein by reference in its entirety.

The present invention relates to an axial gap type electric motor used in various devices such as an electric brake device.

The following proposals have been made for electric motors.
1. An electric brake device using a motor and a linear motion mechanism (Patent Document 1).
2. An electric brake device in which an electric motor is arranged on a parallel axis different from the rotation axis of the linear motion mechanism (Patent Document 2).
3. Axial gap type motor (Patent Document 3).
4). A method of manufacturing an iron core of an axial gap type motor that winds a ribbon-shaped magnetic plate to be a core (Patent Document 4).

JP-A-6-327190 Japanese Patent Laid-Open No. 11-356016 Japanese Patent Laid-Open No. 3-15255 JP 2010-233324 A

In an electric brake device using an electric linear actuator as described in Patent Document 1, it is generally desired to realize an electric actuator that is as space-saving and highly responsive as possible. As an electric motor structure that enables high torque while saving space, for example, axial gap type electric motors as disclosed in Patent Documents 2 to 4 are known. As for the coil of the axial gap type electric motor, an edgewise coil using a rectangular wire that is superior in terms of space factor and heat dissipation is often used.

When wiring in a space-saving manner using a rectangular wire coil, the number of turns per slot of the stator cannot be increased due to the thickness of the rectangular wire, and therefore, a plurality of coils are often connected in series. In this case, the coil ends are at different positions in the axial direction with respect to the coils arranged in the circumferential direction of the shaft of the electric motor. For this reason, it is necessary to wire the coils three-dimensionally, the wiring structure becomes complicated, and the wiring for coupling the coils becomes long, so that the copper loss increases. Moreover, it may be a problem in terms of size and cost.

An object of the present invention is to provide an axial gap type electric motor capable of simplifying a wiring structure of a motor coil, reducing copper loss and reducing costs.

The electric motor of the present invention is an axial gap type electric motor in which a stator and a rotor rotatable relative to the stator face each other in the axial direction of the rotor,
In the stator, a plurality of coils forming magnetic poles are arranged in the rotation direction of the rotor, and as these coils, the winding directions are opposite to each other and the winding ends are positioned at both ends in the axial direction. A coil and a reverse winding coil,
Each of the plurality of coils includes a plurality of coil groups in which the forward winding coil and the reverse winding coil are alternately arranged in the rotation direction, and the plurality of coils constituting the same coil group are arranged in the circumferential direction. The winding ends at the same axial position are coupled between the coils arranged side by side.

According to this configuration, space saving and high response can be achieved by the axial gap type electric motor. In addition to this axial gap type, the plurality of coils are alternately arranged in the rotation direction with a normal winding coil and a reverse winding coil whose winding directions are opposite to each other and each winding end is positioned at each axial end. Therefore, the electric motor can be configured without adding new components or the like.

In addition, a plurality of coils constituting the same coil group may generate magnetic fluxes in the same direction by coupling winding ends in the same axial direction between coils connected in the circumferential direction in the coil group. The coils can be wired in the shortest distance because they are electrically connected in series. For this reason, motor copper loss can be reduced. Coil ends connected to each other in the same axial direction between coils adjacent to each other in the circumferential direction, so that the coil wire does not entangle in the axial direction and the radial direction in a complicated manner. Therefore, the wiring structure can be simplified. Therefore, the manufacturing cost of the electric motor can be reduced and the motor size can be made compact.

In the plurality of coils coupled in series, input / output ends of currents to the winding portions forming the magnetic poles may be located on the same plane orthogonal to the axial direction of the rotor. In this case, the connection between the electric motor and the control device for controlling the electric motor becomes easy, which is advantageous in manufacturing.

The forward winding coil and the reverse winding coil are each wound so that conductors are laminated in the axial direction, and the plurality of coils constituting the same coil group are wound by a continuous coil wire. May be. In this case, since a connection part can be reduced, a some coil can be wired in a space-saving, and an electric motor can be comprised compactly. Thereby, the versatility of the electric motor can be enhanced.

The coil wire is a rectangular wire having a rectangular cross section cut along a plane including the axis of the coil wire, the longitudinal direction of the rectangular flat wire in the cross section is orthogonal to the axial direction, and The rectangular flat wire may be arranged such that the short direction in the cross section of the rectangular flat wire is parallel to the axial direction, and the flat wire may be wound so as to be stacked in the short direction. In this case, since the short direction of the rectangular wire is laminated in parallel with the axial direction, there is relatively little ineffective space between the coils, and the coils can be wound, and space saving can be further achieved. . In addition, when a coil using the rectangular wire is used, a stator having high heat dissipation and excellent “space factor” which is a ratio of a conductor to a cross section of the winding can be configured.

The plurality of coil groups constitute excitation magnetic poles of three or more phases having different current phases, and among the coil groups constituting the same phase, wiring between coils arranged in the circumferential direction is provided for each of the coil groups having different phases. , May be provided at different radial positions. In this case, even in a narrow space, wiring can be easily performed without interference between a plurality of coil groups having different phases, so that the wiring structure can be simplified.

The plurality of coil groups constitute excitation magnetic poles of three or more phases having different current phases, and among the coil groups constituting the same phase, wiring between coils arranged in the circumferential direction is provided for each of the coil groups having different phases. , May be provided at different axial positions. In this case, wiring can be performed at the shortest distance without interfering between a plurality of coil groups having different phases, and an insulation distance between the coil wires can be easily ensured.

Any combination of at least two configurations disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of each claim in the claims is included in the invention.

The present invention will be understood more clearly from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to define the scope of the present invention. The scope of the invention is defined by the appended claims. In the accompanying drawings, the same reference numerals in a plurality of drawings indicate the same or corresponding parts.

It is sectional drawing of the electric motor which concerns on one Embodiment of this invention. It is a perspective view which shows notionally the stator of the same electric motor. It is a perspective view of the several coil which comprises the same phase in the same stator. It is a perspective view of the several coil which comprises the other same phase in the same stator. It is a perspective view of the several coil which comprises the other same phase in the same stator. It is the schematic diagram which expand | deployed the same some coil in the rotation direction of the rotor. It is the schematic diagram which expand | deployed the several coil of the prior art example in the rotation direction of the rotor. It is sectional drawing which shows the linear motion actuator using the same electric motor.

An electric motor according to an embodiment of the present invention will be described with reference to FIGS.
<Overall structure of axial gap motor>
As shown in FIG. 1, the electric motor M includes a housing 1, a stator 2, and a rotor 3. The electric motor M is an axial gap type in which the stator 2 and the rotor 3 face each other in the axial direction of the rotor 3. The stator 2 is statically held by the housing 1. The rotor 3 is supported so as to be rotatable with respect to the stator 2. A rotating shaft 5 is rotatably supported on the housing 1 via a bearing 4, and a rotor 3 is fixed to the outer periphery of the rotating shaft 5.

The housing 1 is composed of a plurality of divided

housings

1A and 1B, and a stator 2 is installed in one of the divided housings 1A. The other divided housing 1B also serves as a housing of the motor using device 6 that uses the electric motor M, that is, a part of the housing of the motor using device 6 becomes a motor housing. The motor using device 6 includes, for example, a linear actuator described later.

The axial gap type electric motor M is a permanent magnet type synchronous motor, and the stator 2 is an excitation mechanism for an assembly part having an iron core 7 and a coil 10. The rotor 3 is formed by embedding a plurality of permanent magnets 3a arranged in the circumferential direction in a disc-shaped holding member 3b. The holding member 3b may be a metal member or a resin member. The rotor 3 may be entirely made of a magnetic material. In that case, the rotor 3 is formed into a shape having a saliency in which the reluctance varies in synchronization with the rotation, so that a reluctance type synchronous motor is obtained.

<About the structure of the stator>
As shown in FIG. 2, the iron core 7 in the stator 2 has a back yoke 8 and a plurality of cores 9. As shown in FIGS. 1 and 2, the back yoke 8 is a cylindrical or annular flat plate concentric with the rotation axis O of the rotor 3 and extending in the circumferential direction of the rotation shaft 5, and a magnetic path between the magnetic poles. Form. The cores 9 protrude from the back yoke 8 in the axial direction of the rotor 3 and are arranged at equal intervals in the circumferential direction of the rotor 3 to form magnetic poles. The number of the cores 9 is preferably an integer multiple of the number of phases of the alternating current to be applied, so that a high-output motor can be configured. For example, since the illustrated example is a three-phase motor, the number of cores 9 is twelve, which is four times the number of phases “3”. However, the number of cores 9 may be configured to be 11 in total: 4 U phases, 4 V phases, and 3 W phases.

The end surface of the core 9 in the axial direction faces the rotor 3 to form a magnetic pole, and the direction of the magnetic pole is parallel to the axial direction of the rotor 3. The coils 10 and the iron cores 7 are arranged at equal intervals in the circumferential direction (equal distribution), and the equal distribution directions of the coils 10 and the iron cores 7 coincide with the rotation direction of the rotor 3. For simplicity, some structures such as insulators and wiring are omitted.

<< About Coil 10 >>
In the stator 2, a plurality of coils 10 forming magnetic poles are arranged in the rotation direction of the rotor 3. As the plurality of coils 10, there are two types, a normal winding coil 10a and a reverse winding coil 10b, in which the winding directions are opposite to each other and the respective winding ends are positioned at both ends in the axial direction. The plurality of coils 10 includes a plurality (three in this example) of coil groups 11 configured such that the forward winding coil 10a and the reverse winding coil 10b are alternately arranged in the rotation direction. The plurality of coil groups constitute U, V, and W three-phase excitation magnetic poles having different current phases.

The same coil group 11, that is, a plurality of coils constituting the same phase, are wound around a continuous coil wire Ce. The coil wire Ce is a rectangular wire having a rectangular cross section cut along a plane including the axis L1 of the coil constituted by the coil wire Ce. That is, an edgewise coil using a rectangular wire is used as the coil. The rectangular flat wire is disposed such that the longitudinal direction of the cross section of the rectangular wire is perpendicular to the axial direction, and the short direction of the rectangular flat wire is parallel to the axial direction. It is wound so as to be laminated in the direction.

As shown in FIG. 6A, in the plurality of coils constituting the same coil group 11 (same phase), the forward winding coil 10a and the reverse winding coil 10b are alternately arranged in the rotation direction, and the

coils

10a and 10b adjacent in the circumferential direction are arranged. The same axial winding ends are coupled to each other. By being coupled in this way, they are electrically coupled in series so as to generate magnetic flux in the same direction. As shown in FIG. 2, for a plurality of coils 10 connected in series, the current input / output terminal 13 to the winding part 12 forming the magnetic pole is the same plane orthogonal to the axial direction of the rotor 3 (FIG. 1). Located on the top.

As shown in FIG. 3 to FIG. 5, in each coil group 11, for example, the coil wire is forward-wound from the current input / output end 13 which is the winding end at the lower end in the axial direction provided in the lower left in FIG. winding wound as 10a, the first winding portion 12 ₁ is completed at the winding end 14 of the axial base end side of the rear side in FIG. 3. When the winding portion 12 is viewed from the distal end side in the axial direction, the winding direction of the winding portion 12 that spirals from the winding end on the distal end side in the axial direction to the winding end 14 on the proximal end side in the axial direction is clockwise. The winding part 12 is referred to as a “normally wound coil”. When the winding portion 12 is viewed from the distal end side in the axial direction, the winding direction of the winding portion 12 that spirals from the winding end on the distal end side in the axial direction to the winding end 14 on the proximal end side in the axial direction is counterclockwise. The surrounding winding portion 12 is referred to as a “reverse winding coil”. The first winding portion 12 ₁ coil wire Ce from the winding end 14 of the axial base end side of, to be drawn to the rotational axis radially inward. As shown in FIG. 2, the wiring 15 between the winding

parts

12 and 12 adjacent to each other in the circumferential direction among the plurality of coils 10 constituting the same phase is provided at different radial positions for each phase and intersects each other. There is no such thing.

The wiring 15 between the winding

portions

12 and 12 of the plurality of coils constituting the U phase in FIG. 3 is provided at the radial position on the outermost diameter side, and winding of the plurality of coils constituting the W phase in FIG. The wiring 15 between the

portions

12 and 12 is provided at a radial position closest to the inner diameter side. The wiring 15 between the winding

parts

12 and 12 of the plurality of coils constituting the V phase in FIG. 4 is provided at a radial intermediate position between the

wirings

15 and 15 in FIGS. Accordingly, as shown in FIGS. 3 to 5, the wiring 15 between the winding

portions

12 and 12 of the three phases U, V, and W is wired in the circumferential direction of the rotational axis in a different positional relationship in the radial direction of the rotational axis. , it reaches the second winding portion 12 of the _second axial base end side winding end 14.

The second winding portion 12 _2, when viewed from the axial direction distal end side coil wire Ce is wound so as to reverse wound coil in the opposite winding direction from the first winding portion 12 ₁ . Specifically, the second winding portion 12 _2, for example, coil wire Ce to the near side from the winding end 14 of the axial base end side of the rear side is wound spirally in FIG 3, Figure 3 an axial tip end side of the winding end at the second winding portion 12 ₂ of the front side in is completed. When a plurality of coils are arranged in this way, when a current is applied from the input / output terminal 13, the direction of the magnetic field generated in each winding part 12 electrically connected in series is each slot part in phase with the polarity of the current. Match in

From the winding end of the axial tip side of the second winding portion 12 ₂ is completed, in the same manner as above coil wire Ce is drawn to the rotating shaft radially inward, the coil wire toward the third winding portion 12 ₃ Ce is wired. In addition, the wiring 15 between the winding

parts

12 and 12 adjacent to the circumferential direction among the some coils which comprise the same phase may be provided in a different axial position for every phase.

For example, in the depth direction in FIG. 3 corresponding to the rotation axis direction, the wiring 15 between the winding

portions

12 and 12 positioned on the back side and the wiring 15 between the winding

portions

12 and 12 positioned on the near side are: If the position is different in the direction of the rotation axis for each phase, the wiring length is the shortest and the insulation distance between the coil wires is easily secured. For example, in an electric motor that is flatter in the axial direction, the wiring position may be adjusted as appropriate based on the convenience of the motor size and the like, such that the axial position of the wiring is relatively close. Thereafter, the third and fourth winding

portions

12 ₃ and 12 ₄ are similarly formed so that the winding directions of the coil wires Ce viewed from the same axial front end side are in an alternating relationship.

In a fourth winding portion terminal end 16 is 12 winding end of the axial tip end side of the ₄ shown in FIG. 2, to connect the ends of the three phases, respectively, a star three-phase alternating current circuit (not shown) Form. As shown in FIG. 2, when the motor current is connected on the inner diameter side except for the input / output end 13, the wiring distance is shortened, the efficiency is increased, and the outer diameter side where the magnetic pole area is relatively wide is connected to the magnetic pole. Effectively used to improve torque. However, a part or the whole of the wiring part may be configured to be wired on the outer diameter side.

<Comparison of motor coil wiring structure of this embodiment and conventional structure>
FIG. 6A is a schematic diagram in which a plurality of coils of the present embodiment are developed in the rotation direction of the rotor (rotational axis circumferential direction). FIG. 6B shows the case of using a coil wound in the same direction, which is a conventional structure. This conventional structure requires the wiring 15 between the coils to be routed in the direction of the rotation axis as compared with the wiring structure of the embodiment. For this reason, especially as the number of phases increases, the wiring structure becomes complicated, the wiring space increases, and the cost may increase. In the conventional structure, for example, when an axial gap motor with 12 cores is used in a three-phase motor, the wiring of the other phase coil and the wiring in the same slot must be avoided when wiring. In addition, the copper loss may increase because the wiring length is eliminated.

<About the effects>
According to the electric motor M of this embodiment described above, space saving and high response can be achieved by the axial gap type electric motor. The plurality of coils 10 includes a plurality of coils each having a winding direction opposite to each other and a forward winding coil 10a and a reverse winding coil 10b each having a winding end positioned at both ends in the axial direction alternately arranged in the rotation direction. Since it consists of the group 11, an electric motor can be comprised without adding a new component.

In addition, a plurality of coils constituting the same coil group 11 (same phase) generate magnetic fluxes in the same direction by coupling the winding ends in the same axial direction between coils adjacent in the circumferential direction. The coils can be wired in the shortest distance because they are electrically connected in series. For this reason, motor copper loss can be reduced. Coil ends at the same axial position are coupled between coils adjacent to each other in the circumferential direction, so that the coil wire Ce is not complicatedly entangled in the axial direction and the radial direction. Since wiring between them becomes easy, the wiring structure can be simplified. Therefore, the manufacturing cost of the electric motor M can be reduced and the motor size can be made compact.

Since the input / output end 13 of the current to the winding part 12 is located on the same plane orthogonal to the axial direction of the rotor 3, an electric motor M and a control device (not shown) for controlling the electric motor M are shown. Connection), which is advantageous in manufacturing. The forward winding coil 10a and the reverse winding coil 10b are respectively laminated in the axial direction, and the plurality of coils constituting the same coil group 11 are wound by a continuous coil wire Ce. Wiring can be performed in a space, and the electric motor M can be made compact. Thereby, the versatility of the electric motor M can be improved.

Since the short direction of the rectangular wire is laminated in parallel with the axial direction, the electric motor M can be wound around the coil with relatively little ineffective space between the coils, and space saving can be further achieved. Can do. Further, since the coil using the rectangular wire is used, the stator 2 having high heat dissipation and excellent “space factor” which is the ratio of the conductor to the cross section of the winding can be configured. Since the wiring 15 between the winding

parts

12 and 12 adjacent to each other in the circumferential direction among the plurality of coils constituting the same phase is provided at different radial positions for each phase, the wiring 15 is circular even in a narrow space. Since the wiring 15 between the winding parts 12 adjacent to each other in the circumferential direction becomes easy, the wiring structure can be simplified.

<About other embodiments>
In the above-described embodiment, an example of star connection in which the ends of three-phase coils are connected is shown. For example, the input / output ends of the currents of the three phases are connected to both ends of the winding portion of another phase. Thus, a delta connection can be configured. About the positional relationship in the radial direction of each of the three phases of the wiring between the winding portions, the phase sequence may be the same in the radial direction in the wiring portion on the axial base end side and the wiring portion on the distal end side in the axial direction, Alternatively, for example, the phase order of the wiring portion on the proximal end side in the axial direction and the wiring portion on the distal end side in the axial direction may be reversed. The above-described arrangement can be appropriately determined according to the manufacturing convenience such as the winding process.

In the embodiment described above, in the wiring part between the winding parts, the wiring part is shown in an arrangement in which the longitudinal direction of the cross section cut by a plane including the axial direction is parallel to the axial direction and the three phases are arranged in the radial direction. The arrangement is not limited to this. For example, the wiring portion may be arranged in such a manner that a short direction of a cross section cut along a plane including the axial direction is parallel to the axial direction and three phases are aligned in the axial direction. Thus, by arranging the short side direction of the wiring portion in parallel with the axial direction and arranging the three phases in the axial direction, it is possible to wire in a space-saving manner.

In the above-described embodiment, an example of three-phase 12 slots is shown, but the number of phases is appropriately determined according to the design. Further, for example, a configuration of four or more phases mainly in a reluctance motor may be used, or a two-phase configuration may be used as in a brushed DC motor.

In addition, in the above-described embodiment, an example in which the iron core of the stator includes a back yoke is shown, and a single gap type motor having a pair of magnetic poles using the stator, or magnetic poles on both sides of the rotor. A double stator type axial gap motor having stators at both ends can be configured. In place of the stator of the previous embodiment, the back yoke is not provided, or the structure of the embodiment is provided on both sides of the back yoke so that the stator has magnetic poles on both sides, and the rotor is provided on both sides. A double rotor type axial gap motor can also be configured. Moreover, it is good also as a multistage type axial gap motor combining these structures.

<Application example of electric motor>
FIG. 7 is a simplified cross-sectional view of an electric linear actuator using a double stator type axial gap motor. A linear motion mechanism 101 is installed coaxially with the axial gap type electric motor M. The linear motion mechanism 101 includes a ball screw mechanism that is rotationally driven by the rotary shaft 5 of the electric motor M, and converts the rotational motion of the electric motor M into linear motion of the linear motion portion 102. The motor-using device 6 that is the electric linear motion actuator is used, for example, in an electric brake device for braking an automobile wheel, and the linear motion portion 102 is in contact with a brake rotor 103 provided on the wheel of the automobile. It is used for advancing and retracting driving of the friction pad 104 to be separated.

According to this electric linear actuator, since the axial gap type electric motor M is provided, it is possible to realize an electric brake device that enables high torque in a small space. For this reason, the versatility which mounts an electric brake device in a vehicle can be improved. Moreover, by simplifying the wiring structure of the motor coil as described above, it is possible to reduce the copper loss and reduce the cost. The wiring part may be molded with, for example, a resin material. Such a structure is strong against vibrations and the like, and is suitable for operation under severe environmental conditions such as when used as an actuator for an electric brake device.

As described above, the preferred embodiments have been described with reference to the drawings, but various additions, modifications, and deletions are possible without departing from the spirit of the present invention. Therefore, such a thing is also included in the scope of the present invention.

2 ... Stator 3 ... Rotor 10 ... Coil 10a ... Forward winding coil 10b ... Reverse winding coil 11 ... Coil group 12 ... Winding part 13 ... Input / output end Ce ... Coil wire

Claims

A stator and a rotor rotatable with respect to the stator are axial gap type electric motors facing in the axial direction of the rotor,
In the stator, a plurality of coils forming magnetic poles are arranged in the rotation direction of the rotor, and as these coils, the winding directions are opposite to each other and the winding ends are positioned at both ends in the axial direction. A coil and a reverse winding coil,
Each of the plurality of coils includes a plurality of coil groups in which the forward winding coil and the reverse winding coil are alternately arranged in the rotation direction, and the plurality of coils constituting the same coil group are arranged in the circumferential direction. An electric motor in which the winding ends at the same axial position are coupled between coils arranged side by side.
2. The electric motor according to claim 1, wherein an input / output terminal of a current to a winding portion forming the magnetic pole is on the same plane orthogonal to the axial direction of the rotor for the plurality of coils coupled in series. Electric motor located.
The electric motor according to claim 1, wherein the forward winding coil and the reverse winding coil are wound so that conductors are laminated in the axial direction, and a plurality of coils constituting the same coil group are An electric motor wound by a continuous coil wire.
4. The electric motor according to claim 3, wherein the coil wire is a rectangular wire having a rectangular cross section cut along a plane including the axis of the coil wire, and a longitudinal direction of the rectangular flat wire in the cross section is Winding so that the short direction in the cross section of the rectangular flat wire is perpendicular to the axial direction and parallel to the axial direction, and the flat wire is laminated in the short direction. The electric motor being turned.
5. The electric motor according to claim 4, wherein the plurality of coil groups constitute excitation magnetic poles of three or more phases having different current phases, and wiring between coils arranged in a circumferential direction among the coil groups constituting the same phase. Is an electric motor provided at a different radial position for each coil group having a different phase.
5. The electric motor according to claim 4, wherein the plurality of coil groups constitute excitation magnetic poles of three or more phases having different current phases, and wiring between coils arranged in a circumferential direction among the coil groups constituting the same phase. Is an electric motor provided at a different axial position for each coil group having a different phase.